From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56F48C433E9 for ; Fri, 15 Jan 2021 13:27:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 25F432339E for ; Fri, 15 Jan 2021 13:27:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731610AbhAON1Z (ORCPT ); Fri, 15 Jan 2021 08:27:25 -0500 Received: from mx2.suse.de ([195.135.220.15]:46762 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730617AbhAON1Z (ORCPT ); Fri, 15 Jan 2021 08:27:25 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id BE98FAC8F; Fri, 15 Jan 2021 13:27:00 +0000 (UTC) Date: Fri, 15 Jan 2021 14:26:58 +0100 From: Oscar Salvador To: Muchun Song Cc: mike.kravetz@oracle.com, akpm@linux-foundation.org, n-horiguchi@ah.jp.nec.com, ak@linux.intel.com, mhocko@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Michal Hocko , stable@vger.kernel.org Subject: Re: [PATCH v6 4/5] mm: hugetlb: fix a race between isolating and freeing page Message-ID: <20210115132658.GB10102@linux> References: <20210115124942.46403-1-songmuchun@bytedance.com> <20210115124942.46403-5-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210115124942.46403-5-songmuchun@bytedance.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Fri, Jan 15, 2021 at 08:49:41PM +0800, Muchun Song wrote: > There is a race between isolate_huge_page() and __free_huge_page(). > > CPU0: CPU1: > > if (PageHuge(page)) > put_page(page) > __free_huge_page(page) > spin_lock(&hugetlb_lock) > update_and_free_page(page) > set_compound_page_dtor(page, > NULL_COMPOUND_DTOR) > spin_unlock(&hugetlb_lock) > isolate_huge_page(page) > // trigger BUG_ON > VM_BUG_ON_PAGE(!PageHead(page), page) > spin_lock(&hugetlb_lock) > page_huge_active(page) > // trigger BUG_ON > VM_BUG_ON_PAGE(!PageHuge(page), page) > spin_unlock(&hugetlb_lock) > > When we isolate a HugeTLB page on CPU0. Meanwhile, we free it to the > buddy allocator on CPU1. Then, we can trigger a BUG_ON on CPU0. Because > it is already freed to the buddy allocator. > > Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage") > Signed-off-by: Muchun Song > Reviewed-by: Mike Kravetz > Acked-by: Michal Hocko > Cc: stable@vger.kernel.org Reviewed-by: Oscar Salvador -- Oscar Salvador SUSE L3